https://doi.org/10.37229/fsa.fjb.2026.09.07

This study aimed to evaluate the quality of vegetable oil used in the traditional production of unpackaged potato chips marketed in Mosul City, Iraq. Potato chips were prepared using palm oil at 170–180 °C for 3–5 min from potato slices (2–3 mm thick) after soaking in water for 30 min. Random samples were collected during 2025, and oil quality was evaluated weekly over a period of 10 weeks. Oil quality was assessed by determining peroxide value (PV), free fatty acids (FFA), oil absorption, p-anisidine value (p-AV), and volatile compounds using gas chromatography–mass spectrometry (GC–MS). The results showed considerable variation among the collected samples, indicating inadequate control of frying conditions and oil management practices. Peroxide values ranged from 32.6 to 41.1 meq O₂/kg oil, while free fatty acid values and oil absorption ranged from 1.28–3.33% and 31–41%, respectively. The addition of garlic powder, salt, or hot pepper after frying had no significant effect (P > 0.05) on oil absorption, peroxide value, free fatty acid content, or p-anisidine value. GC–MS analysis identified several volatile compounds associated with lipid oxidation and thermal degradation, including 2-hexylfuran, (E,E)-2,4-decadienal, (E,E)-2,4-nonadienal, hexyl formate, 3-methyltetrahydrofuran, methylcyclopentane, and 3-methyl-1-penten-4-yn-3-ol, with relative abundances ranging from 0.56% to 0.80%. The detection of these compounds confirms the formation of primary and secondary lipid oxidation products during repeated frying and supports the conventional physicochemical indices used to assess frying oil deterioration. These findings demonstrate that GC–MS is a valuable complementary analytical tool for monitoring chemical changes in frying oils and improving the quality assessment of traditionally produced potato chips.